When standing in front of a urinal (or a regular toilet for the private types), you release your hand(s) from your johnson in the middle of peeing, leaving it free to guide the urine to its final destination without assistance.

Commonly activated whilst texting, or more rarely, when reading.

Once his pee-stream was safely pointed in the right direction, Ignacius disengaged his hand and entered autopilot mode.

Used for the professional drunk. When you drink so much and so often you function even when you are blackout drunk. You are so good at it your friends and even professional bartenders can't tell you should have been cut off 5 drinks ago. You continue to talk and walk but have no idea what you are saying or doing. This also makes for fun Sherlock holmes mornings.

An extremely high level of drunkeness only achievable through years of alcohol abuse. The individual in autopilot will likely do the following:
Insult you
Hit on you
Scream curse words and racial slurs
Just plain scream
Vomit in hard to clean locations
Lose bowel and bladder control
Question your sexuality
Question their own sexuality

Sleep with sea monsters
Become a legend

Dudes. Jake was So far in autopilot last night! He tongue punched Michelle's nasty fart box after Ian J.O.ed into a rubber and put it in his ass. He also vomited in his underwear while he was wearing them! He doesn't even know it either!